This invention relates to an automatic seat belt device for a vehicle and, more particularly, to improvements in an automatic seat belt device having a guide arm for moving a seat belt webbing forwardly of a seat in response to the opening of an automotive door and guiding the webbing to a position for restricting a passenger in response to the closing of the door.
A conventional automatic seat belt device has, as shown in FIG. 1, a driving circuit for a guide arm. This driving circuit has a door switch A which includes a movable contact B, an open side contact C and a closed side contact G. When the door of a vehicle is opened, the movable contact B of the door switch A is contacted to the open side contact C. The driving circuit further has a limit switch D which is connected at its input terminal to the open side contact C, and another limit switch H which is connected at its input terminal to the closed side contact G. When the movable contact B is contacted to the open side contact C as described above, a circuit E from the limit switch D through the open side contact C, the movable contact B to the ground is closed. If the limit switch D is closed at this time, a driving circuit F is formed from the output terminal of the limit switch D through the driving circuit F having a motor M and is operated to rotate the guide arm of a seat belt webbing (not shown) forwardly of the seat.
The above-mentioned limit switch D is provided at a position for limiting the rotating position of the guide arm. When the limit switch D is operated by the guide arm, the switch D is opened to thereby open the circuit E from the limit switch D through the open side contact C, the movable contact B to the ground, and is operated to stop the rotation of the guide arm.
This driving circuit for driving the guide arm is constructed to open or close the driving circuit F having the motor M by the opening or closing of the door switch A irrespective of the operation or release of an emergency buckle (not shown). Thus, this driving circuit has such disadvantages that the guide arm repeatedly telescopes. Therefore, when an infant's seat belt is used on the seat and the adult's seat belt is not used on the seat, the guide arm is driven.